#include <event2/listener.h>
#include <event2/bufferevent.h>
#include <event2/buffer.h>
#include <arpa/inet.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>

static void echo_read_cb(struct bufferevent* bev, void * ctx)
{
    /* This callback is invoked when there is data to read on bev. */
    struct evbuffer* input = bufferevent_get_input(bev);
    struct evbuffer* output = bufferevent_get_output(bev);
    /* Copy all the data from the input buffer to the output buffer. */
    evbuffer_add_buffer(output, input);
}
static void echo_event_cb(struct bufferevent* bev, short events, void * ctx)
{
    if (events & BEV_EVENT_ERROR)
    perror("Error from bufferevent");
    if (events & (BEV_EVENT_EOF | BEV_EVENT_ERROR)) {
        bufferevent_free(bev);
    }
}
/**
 * @brief  有新连接时的回调函数
 * @note   
 * @param  listener: 
 * @param  fd: 
 * @param  address: 
 * @param  socklen: 
 * @param  ctx: 
 * @retval None
 */
static void accept_conn_cb(struct evconnlistener* listener,
evutil_socket_t fd, struct sockaddr* address, int socklen,void* ctx)
{
    /* We got a new connection! Set up a bufferevent for it. */
    struct event_base* base = evconnlistener_get_base(listener);
    struct bufferevent* bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE);
    bufferevent_setcb(bev, echo_read_cb, NULL, echo_event_cb, NULL);
    bufferevent_enable(bev, EV_READ|EV_WRITE);
}
static void accept_error_cb(struct evconnlistener* listener, void * ctx)
{
    struct event_base* base = evconnlistener_get_base(listener);
    int err = EVUTIL_SOCKET_ERROR();
    fprintf(stderr, "Got an error %d (%s) on the listener. "
    "Shutting down.\n", err, evutil_socket_error_to_string(err));
    event_base_loopexit(base, NULL);
}

int main(int argc, char** argv)
{
    struct event_base* base;
    struct evconnlistener* listener;
    struct sockaddr_in sin;

    /* 1.获取端口号 */
    int port = 10086;
    if (argc > 1) {
        port = atoi(argv[1]);
    }
    if (port<=0 || port>65535) {
        puts("Invalid port");
        return 1;
    }
    base = event_base_new();
    if (!base) {
        puts("Couldn’t open event base");
        return 1;
    }

    /* 2.填写地址 */
    memset(&sin, 0, sizeof(sin));
    sin.sin_family = AF_INET;
    sin.sin_addr.s_addr = htonl(0);
    sin.sin_port = htons(port);

    /* 3.启动监听并设置监听回调函数 */
    listener = evconnlistener_new_bind(base, accept_conn_cb, NULL,
            LEV_OPT_CLOSE_ON_FREE|LEV_OPT_REUSEABLE, -1,
            (struct sockaddr * )&sin, sizeof(sin));
    if (!listener) {
        perror("Couldn’t create listener");
        return 1;
    }
    evconnlistener_set_error_cb(listener, accept_error_cb);
    event_base_dispatch(base);

    return 0;
}


